Bella has a HomeAgain chip, which is manufactured by Merck. It was sold through our vet. We do not pay extra for the annual registry--once the animal is chipped, it's in their system permanently. The extra bells and whistles for $19.99 per year are not necessary. It's a high quality chip. I'm not sure of the frequency, but most dog chip scanners read all chip frequencies anyway. Here is their website:
Pet Microchip FAQs for Vets & Shelters | HomeAgain Pet Microchip. From the website: "Once registered, microchips remain in the HomeAgain database permanently and may be updated online at no charge anytime by logging into HomeAgain.com, regardless of annual membership status."